Hydraulic device with case drain system

A method for operating a hydraulic device including a housing with a case area for holding case fluid, the hydraulic device coupled to a hydraulic fluid reservoir containing hydraulic fluid, the method comprising the steps of:

• rotating an actuator, the actuator coupled to a primary piston and a drain piston;
• using the actuator to operate the primary piston within a primary cylinder of the housing in a first reciprocal motion, the primary cylinder receiving the hydraulic fluid on a primary intake stroke and ejecting the hydraulic fluid on a primary exhaust stroke;
• using the actuator to operate the drain piston within a drain cylinder of the housing in a second reciprocal motion, the drain cylinder receiving the case fluid on a case intake stoke and outputting the case fluid on a case exhaust stroke;
• wherein a portion of the hydraulic fluid becomes the case fluid when the portion enters the case area and the second reciprocal motion causes the case fluid to be transferred from the case inlet to the case outlet.

A hydraulic device comprising:

• a housing having an inlet for receiving hydraulic fluid and an outlet for outputting the hydraulic fluid, the housing having a case area for holding case fluid;
• a primary cylinder positioned in the housing along a first reciprocation axis, the primary cylinder having an input in fluid communication with the inlet for receiving the hydraulic fluid on a primary intake stroke and an output in fluid communication with the outlet for ejecting the hydraulic fluid on a primary exhaust stroke;
• a primary piston positioned for a first reciprocal motion within the primary cylinder along the first reciprocation axis, the primary piston having a first end exposed to the hydraulic fluid and a second end coupled to an actuator;
• the actuator being driven by the second end via the first reciprocal motion, the actuator mounted on the shaft such that the shaft is rotated by the actuator;
• a drain cylinder positioned in the housing along a second reciprocation axis;
• a case inlet for receiving the case fluid, the case inlet located in the case area and fluidly coupled to the drain cylinder;
• a case outlet for outputting the case fluid, the case outlet fluidly coupled to the drain cylinder;
• a drain piston positioned for a second reciprocal motion within the drain cylinder along the second reciprocation axis, the drain piston having a third end exposed to the case fluid in the drain cylinder and a fourth end coupled to the actuator;
• wherein a portion of the hydraulic fluid becomes the case fluid when the portion enters the case area and the second reciprocal motion causes the case fluid to be transferred from the case inlet to the case outlet.

A method for operating a hydraulic device including a housing with a case area for holding case fluid, the hydraulic device coupled to a hydraulic fluid reservoir containing hydraulic fluid, the method comprising the steps of:

• operating the primary piston within a primary cylinder of the housing in a first reciprocal motion, the primary cylinder receiving the hydraulic fluid on a primary intake stroke and ejecting the hydraulic fluid on a primary exhaust stroke;
• driving an actuator by the first reciprocal motion, the actuator coupled to the primary piston, the actuator mounted on a shaft such that said driving causes rotation of the shaft;
• operating the drain piston within a drain cylinder of the housing in a second reciprocal motion facilitated by said rotating, the drain cylinder receiving the case fluid on a case intake stoke and outputting the case fluid on a case exhaust stroke, the drain piston coupled to the actuator;
• wherein a portion of the hydraulic fluid becomes the case fluid when the portion enters the case area and the second reciprocal motion causes the case fluid to be transferred from the case inlet to the case outlet.